<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>圣杯布局Flex</title>
    <style>
        *{
            padding: 0;
            margin: 0;
        }
        html, body{
            width: 100%;
            height: 100%;
        }
        main{
            width: 100%;
            height: 60%;
            display: flex;
        }
        aside{
            width: 20%;
            height: 100%;
            background-color: purple;
        }

        header, footer{
            width: 100%;
            height: 20%;
            background-color: cyan;
        }

    </style>
</head>
<body>
<header>header</header>
<main>
    <aside>main aside</aside>
    <main style="flex: 1;height: 100%">main main</main>
    <aside>main aside</aside>
</main>
<footer></footer>
</body>
</html>
